sarc22 - no.
you are right, the amp doesnt know or care how many speakers it sees. What it does do, is put out a consistant ammount of power at 1-4 ohms. not per speaker, not per ohm, that is the total ammount of power it puts out, period.
if you have 4 speakers, regardless of load from 1-4 ohm, they will each get 150 watts.
Otherwise, EVERY person in car audio would be running xenon amps. Can you immagine a 400 dollar amp that can put 1200 watts to ANY number of subs in the world, so long as you wired em to the correct ohm load? not possible.